RC scripts
Resource configuration scripts are run at system startup and shutdown. The scripts run in an order dictated by their runlevles.
Typical System V UNIX runlevels (BSD is just single and multi user mode):
Run
Level Names and Uses
-------------------------------------
0
Powerdown state; conditions where it is safe to turn the power off.
1 Administrative state. s or S Single-user mode.
2 Multi-user
mode; Normal operating state for isolated, non-networked systems.
3
Remote File Sharing (RFS) state. Alternative state for networking
use. (Normal multi-user state for OSF/1; other Sys V may use state
2).
4 User-definable state. (Also not normally used; state 2 used
instead).
5 Firmware state; Used for some types of maintenance on
some systems.
6 Shutdown and reboot state; used to reboot the
system from some other running state (s, 2, 3 or 4) to state 0 then
immediately back to normal operating
state.
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In Linux and IRIX check out the chkconfig command.
Also be aware of the use of the init command.